IAI Forensic Art cheat sheet

Forensic art is the application of artistic skills and anatomical knowledge to legal matters; core products are facial approximations, composite/evidentiary images, age progressions, and demonstrative exhibits.

The IAI Forensic Art sub-discipline recognizes four main categories: composite art, image modification and enhancement, age progression/progression of age, and facial reconstruction/approximation.

Facial approximation from unidentified skulls is a two-stage method: (1) attach tissue-depth markers at standard craniometric landmarks, (2) model or draw features guided by those depths plus skull morphology.

Tissue-depth data are population-, sex-, and age-specific means with standard deviations; they are guides, not exact measurements, and the artist must reconcile them with individual skull traits such as nasal aperture shape, brow ridge, and malar projection.

Standard craniometric landmarks used for depth placement include nasion, glabella, rhinion, mid-philtrum, menton, gonion, zygion, and supraorbital; each landmark gets a depth value from the reference table for the estimated demographic group.

Composite imagery is built from a witness's memory using feature-by-feature selection (eyes, nose, mouth, face shape, hair); the artist must avoid leading the witness and should record all feature choices and revisions.

Age progression extrapolates predictable aging changes: facial fat redistribution, nasolabial deepening, jowl and eyelid laxity, ear and nose cartilage growth, hairline recession, and skin texture change; it is probabilistic, not identificatory.

Image enhancement/modification must preserve evidentiary integrity: document every step, retain the original file, use non-destructive layers, and label any altered image as a demonstrative aid rather than a factual record.

Court admissibility follows the same reliability framework as other expert evidence (relevance plus reliability, e.g., Daubert factors); forensic artists must be able to state their method, error sources, and the limits of any approximation.

Witness interview for composites should use open-ended recall first, then feature-specific questions; cognitive interview techniques reduce contamination and improve accurate feature recall.

Composite systems vary: feature-based (e.g., FBI/Ident-Kit style) versus holistic/whole-face systems; the choice affects how the witness compares and selects faces, so record which system and version were used.

Facial reconstruction media include clay modeling over a skull cast, 2D drawing over a skull photograph, and 3D digital modeling; each carries different error and should be documented with the method named.

Superimposition compares a photograph to a skull by aligning landmarks (e.g., nasion, menton, orbit outlines); it can support exclusion but is not a positive identification method on its own.

Photo-to-photo comparison and morphological analysis assess feature correspondence (ear shape, nose profile, dental alignment, scars); conclusions should be stated as consistent, inconsistent, or inconclusive, not as certainty.

Age progression for missing persons should produce a range of appearances, not a single face, and should be updated periodically; note the assumed aging rate and reference photos used.

Documentation standards: maintain a case file with source images, dates, software versions, artist notes, and all intermediate versions; chain of custody applies to digital files just as to physical evidence.

Uncertainty communication: use calibrated language (e.g., 'approximation,' 'consistent with,' 'cannot be determined') and avoid overstating identification; juries may over-weight realistic facial images.

Ethical and legal limits: do not alter evidence to match a suspect, do not present a reconstruction as a photograph, and disclose any artistic assumptions (e.g., hairstyle, eye color, clothing) that were not derived from evidence.